Power transmission



N F. T. HARRINGTON EQTAL 2,363,179

POWER TRANSMISSION Filed Feb. 21, 1942 2 Sheets-Sheet 2 I INVENTORS FERRIS T. HARRINGTON KAMILL SEIDEL &

BY ROBERT A. SHARTLE ATTORNEY Patented Nov. 21, 1944 i an l r I a ii lZOWEBFMSMISSION H para. :a nun mmxnemit, in main Sada,

. jGrosseiPointej'Earms, TMiclL, andflio lirt A. r 5 i Shar tlaRockIorfl, 111., lassignorstoWicke -s EIncorporated, Detroit, a corporation o fl.

ichi an;

1 i Wh msot her asa fluid motor. i i i r The invention is particularly iooncerned with} system wherein a plurality of motors imust ibe operated from a single ump, and-particularly :to systems where onevof the motors" should 'ihave In the idrawingszw t r as hydraulic power' transmission system of Figure 1 showing the controls "in different operating positions.

a Referring now' towEig-ures 1,40 represents a -;suitable prime-maven such as an internal com precedenceq over another in receiving operating bustiomengine,adapteditohdriveapumpl2 which fluid from thesource. i may bea rotaryl feed pump ofanysuitablecon- IAs aniexample of'situaticns \where the present. struction. The pump 12 hasia suction conduit invention is particularly useful, the caseflof a lliifor withdrawing fluid from a t'ank i5 and -a power-operated dump truck may be considered. \dellveryiconduit ll for vdireoting the delivery The larger sizesof suc'htrucks require someiorm ithere'from tofone port otacombination control of steering boosterto amplify themanua'l eflort valve generally designated 22; The latter comof theoperator in turningfthe huge wheels and prises :a unitary block includinga pressure recontrolling them overithe rough imam enc'ollm spon'sive sequence valvefl having annular ports Jteredon excavatingprojects. Hydraulic steering I H, 13 landli formed at spaced positions along boosters for this purpose havebeena standard bore-26. Valve spoo128is slidable across: the commodityaonthemarketIior several years and aports toselectivelyconnect port 13 either with i are admirably ultediorthis purpose." An ;in:- port ltlnas illustrated, whenlnits lefthand posiherent characteristic o! such boosters, however, ition,:.or with port :15 when in its righthand posih thaltvwhin I O a tually Ioperatlngto 25 ation. A spring normally biases the valve steer the vehiclegthey bypassor'unload the pump? spool 28150 the left, The left end of thefbore -or, aslis termed in the art, they operate ion an 2Bis indirect communication with a bore 32 of open-center condition. "Ihishmeans that the :reduceddiameter which is connectedto a source pumpwhich suppliesthe steering Lboostercannot ofpressuresupplylor shifting the valve spool bemadeavailable'for operatingother hydraulic 30 2l to the rightLf r motors such as the body -dumping cylinder. Combination control {valve 22a1soincludes a When the steering booster isactua'IIy operatin three-way, directional valve 34 which comprises itrequiresthetfull deliveryland pressure capacity is Fbore 36 having a plurality of annular ports ofthepump. On the other lphand, when it is not arranged along its length, oii which and -46 operating, it bypasses the pump-and accordingly are-tank ports, and 44 are pressure tports, and disablesit for any other use. i is :a cylinder port. @Communication between [It is anobjectiof the present :invention to prothe various ports is controlled :bya valve spool vide an improved lpower transmissionisystem 48 slidably mounted :in bore 36. Spool 48 conwhich will overcome the above difllculties and itainsthree solid :landsiil, 52 and-54 which, when permit an open-center steering booster to be in neutral position, illustrated, connect ports utilized with a single tpump pressuresource and, and i vand block cylinder port 40. -Spoo1w48 is atthefsame time, to make the pump delivery xalso provldedwith .-a istemiifi whereby the spool available to an auxiliary-motorat such itimes that 148 may be shifted tooany one of three effective the steering zboosteris no't utilizingsuchidelivery. operating positions cbywzmeans of a suitable up- At the same time, the :present inventionzseeksizto erator, Qsuchas designated at 158. A springprovidesuch a system wherein the benefits 0'1 pressed detent is provided for retaining the open-center unloading areaobtained during-such valve: Irictionally in either oneof its three ieitimes as neither .thesteerinzbooste'r ,norithe auxiective positions. The extreme'right end of bore iliarymotor are beingoperated. i 1136isiprovided withanlair ventipassagefl. Further objectsand advantages ofithe'present 60 Tank .port 38 communicates with tank l5 invention will be apparent ifrom the following lthrough conduits :64 and 66; A relief-valve deScriptiOm referencevbeing had to the accornconnects with a :pressurebranch conduit :H for panying drawings wherein a preferred form of limiting the pressure therein to a predetermined the present inventionis clearly shown. maximum by exhausting into the conduit 64.

Tank conduit fl hzis an auxiliary conduit ill .age I28 connected to the rod H8.

which extends to a conduit 12. The latter connects port 48 of valve 34 with the right end of bore 28 of valve 24, servingto drain any leakage that may occur past the spools 48 and 28.

Cylinder port 40 of valve 34 is connected by a conduit I4 which leads to the head end of. a cylinder I8- The latter has .slidably mounted therein a piston 18 which has a rod 80 attached to a dumper 82 for communicating "its motion thereto. The rod end or the cylinder. I8 is connected by the conduit 88 to drain that may occur past'the piston 18.

Ports 42 and 44 of bore-38 communicate with ports n and I of bore 26 throughconduits a4,

and 88, respectively. Conduit88 has 'a branch conduit 88 which extends to the bore 82, and

therefrom to the pressure branch conduit 1|,

passing through a. restriction 80. Conduit 88 extends beyond port I5 of bore 20 to a follow-up valve 82. i

Valve 92 comprises a main body having a longitudinal bore 94 provided with a plurality of annular ports arranged along its length, of which 88 is a pressure port, 88 and I00 aretank ports, and I02 and'I04 are cylinder ports. Pressure port 88 is connected by the conduit 88, while tank ports 88 and I00 are connected-by'conduits I08 and I08, the latter communicating with conduits any leakage v In operation, while pump I2 is being driven by the motor I0, as shown in Figure 1, oil is withdrawn from the tank I8 through the suction conduit I4 and delivered to the delivery conduit I8. The latter directs the fluid to the control valve 22 where it enters port I3 of sequence :valve 24. Spool 28, being in the position shown, directs the liquidthrough port II into conduit 84 which directs it to valve 34 entering port 42. The latter being connected with port 44 causes it to flow into conduit 88 which directs the fluid around valves'pool 28 through port I8 of valve 24 to the follow'y'alve 8 2, entering the latter at pressure Port 88. ,Valve 82, being an open-center valve,-

I08 and 88. Cylinder ports I02 and I04 are connected by conduits I I0 and I I2, respectively, which extend to theopposite .ends of a non-difierential cylinder H4. The latter contains a piston I I8 having rods; I I8 and I20 extending therefrom and adapted to guide the wheels of a vehicle, ,ofwhich one,. I22, is shown.

Within bore 84 of valve 82 there is indie,

vmounted a sleeve member .124 which contains ports 88', 88, I02 and I04, corresponding to those of bore 84. The upper end of the sleev I24 has secured thereto a shaft I28-which is attached to a lever arm I28. The latteris attached to the rod II8 pivoting about a fulcrum I 30.

Valve spool/I32 isslidable across the sleeve ports to selectively eonnect'pressure port" of bore 84, through corresponding sleeve 'ports, with either cylinder port I02.when .in its upper position or with cylinder port I 04 when in its lower position, simultaneously providing for'the discharging liquid to 1 8.5 therethrough to the tank I8. A spring I84 normally biases the valve spool I82 downwardly. Attached to the bottom of spool I32 is an operating stem I88 which extends downward to scam I38 for the operation there-- of. Cam I88 is connected by a rod I40 to a gear rack- I42 which is operated by'a worm gear I44.

wheel I 48' by- The latteris attached to a steering a rod I48.

The operation of the valve 82 is such that, whatever distance the operating plunger I88 is moved by the cam- I38,in either direction from allows the liquid to escape to the tank through both tank ports 88 and I00.

To operate the dumping cylinder I8, valve spool 48 of valve 34 is pulled outward, connecting port 42 with port 40 and blocking port 44, as shown diagrammatically in Figure 2. This directs the liquid entering port 42 to pass through port 40 into the conduit 14 which delivers it to-the dumping cylinder I8. As the liquid is now under pressure, it is caused to flow from pressure branch conduit 'II into branch conduit*88,through restriction 80, andto conduit 88. The latter directs the fluid to the follow-up valve 82 which, being in neutralposition, as shown, directs the liquid to the tank I8 without imposing any resistance. Consequently, the liquid in conduits 88 and 88 is maintained under no appreciable pressure, and the shifting of the sequencev valve spool 28 is prevented.

If, however, while operating the'dumper 82, the

, pump delivery, reducing the pressure in conthe neutral position, liquid flowing therethrough i will cause the cylinder II4 to proportionally duplicate the shaft movement, as is well known'in the art. When no movement is required, the 1 liquid at the pressure port 88 is discharged to the The shutting tank at no appreciable pressure. 011 of the valve 82 is controlled by the valve link- Whatever distance the plunger I88 is moved, th piston I I8 in cylinder I I4 will move a similar or proportional distance, depending on the amplifica-- tion of the lever I28, and shut off the valve 82 by pulling the sleeve I24 until ports I02 and I04 become centered with the spool I82, thus allowing the fluid to discharge to the tank.

duit 88. This will cause sequence valve 24 to be moved 'to the left by the spring 80,-connecting port with port II, resuming the operation or lifting the dumper 82, as'shown in Figure 2.

.To lower the dumper 82, valve spool of valve 84 (Figure 1) is pushed inward, connecting port" 40 with tank port 88,"and port 42 with port 44. This provides for the charge to the tank,

through follow valve 82,'in the manner hereinbefore disclosed.

Thus, it will be seen that this invention provides a means of using the pressure source of a single pump for th operation of a. dump truck booster control, giving precelift and a steering dence to the latter.

While the formwof embodiment'of the inven-' tion as herein disclosed constitutes a preferred form, it is to be understood that other forms mightbe adopted,.all coming within the scope of the claims which follow.

What isclaimed is as follows: 1. In a hydraulic power transmission system the combination of a single pressure source and of follow-up with tank port I00, directing. upper end of the cylinder 4.-

II, directing the steering booster liquid in cylinder 18 to.disbeing forced out of the cyL- inder18 by the weight of the dumper 82, and also allowsthe pump delivery to flow to tank a plurality of fluid motors operable thereby, individual control valves for each motor, one valve being of the open-center type and arranged to bypass fluid from its inlet to its outlet when in neutral position, means connecting another valve to said source and arranged to normally cut oil at least a major portion of the fluid bypassed through the first valve when the second valve is moved to operating position, and means including a pressure responsive valve for cutting off the supply to the second valve and diverting that supply to the first valve and motor whenever the first valve is operated while the second valve is in operating position.

2. In a hydraulic power transmission system the combination of a single pressure source and a plurality of fluid motors operable thereby, and means for selectively delivering fluid from the source to either motor with precedence given-to one or to freely bypass the source when neither motor requires fluid, said means comprising individual selector valves for each motor, one of which unloads the source when in neutral position, means in the other valve for substantially blocking the supply of fluid to said one valve when -the other valve is operated, and a pressure responsive valve for diverting the supply from said other valve to the one valve'whenever the one valve is operated.

3. In a hydraulic power transmission system the combination of a single pressure source and a plurality of fluid motors operable thereby, individual control valves for each motor and providing when all valves are in neutral position a free bypass for the source through the valves in I series, means in each valve for closing such bypass when the valve is shifted to operate its cor-:

responding motor and directing the fluid delivery from the source to the motor and cutting delivery ofi from another valve, whereby the valve which is nearest the source would when oper-,.

ated normally take all thei'source delivery, and a pressure responsive valve for delivering fluid directly from the source to a valve remote from the source and arranged to be operated immediately whenever such remote valve is operated at the same time that said nearest valve is'operated.

4. In a hydraulic power transmission system the combination of a single pressure source and a plurality of fluid motors operable thereby, individual control valves for each motor and providing when all valves are in neutral position a free bypass for the source through the valves in series, means in each valve for closing such bypass when the valve is shifted to operate its corresponding motor and directing the fluid delivery from the source tothe motor and cutting delivery 0115 from another valve, ,whereby the valve which is nearest the source would when operated normally take all the source delivery, and a pressure responsive valve for delivering fluid directly from the source to a valve-remote from the source whenever such remote valve is operated at the same time that said nearest valve is operated, said pressure responsive valve, including a restricted bypass for diverting a small portion of the source delivery to said remote valve while the nearest valve is operated.

5. In a hydraulic power transmission system for vehicle use the combination of a single pump for supplying fluid under pressure, a steering booster having a control valve of the open-centenv type effective )00 bypass the pump when n t tually operating, an auxiliary motor t be ated selectively during intervals when the steering booster is not operating, and a combined manual and pressure-controlled selector valve assembly connected between the pump and the steeringv booster and containing means for directing the pump delivery to the auxiliary motor a at only such times as the booster control valve is in pump bypassing position.

6. In a hydraulic power transmission system for vehicle use the combination of: a; single pump for supplying fluid under pressure, a steering booster having a control valve of the open-center type effective to bypass the pump when not actually operating, an auxiliary motor to be operated selectively during intervals when the steering booster is not operating, a combined manual and pressure-controlled selector valve assembly -connected between the pump and the steering booster and containing means for directing the pump delivery to the auxiliary motor at only such times as the steering booster is in pump bypassing position, said means comprising a restricted diverter passage for delivering a limited. flow from the pump through the booster control valve while the major flow takes place to the auxiliary motor, and a valve responsive to pressure conditions insaid diverter passage for transferring the full pump delivery to the booster control valve whenever the latter is shifted to operating position. i

FERRIS T. HARRINGTON.

KAMILL SEIDEL. ROBERT A. SHARTLE. 

